Impulse repeater



May 9,1944.

H. G. EVERS ETAL IMPULSE REPEATER Filed Feb. 15, 1943 POLARIZED 2 Sheets-Sheet 1 R4) (cl FIG.2

IN V EN TORS HARRY 6. EVERS GEORGE ELLIOTT ATTORNEY May 9, 1944.

H. G. vans ETAL IMPULSE REPEATER 2 Sheets-Sheet 2 Filed Feb. 15, 1945 INVENTORS HARRY 6. EVERS GEORGE ELLIOTT ATTORNEY Patented May 9, 1944 IMPULSE REPEAT'ER Harry G. Evers and George Elliott, Chicago, Ill., assignors to Automatic Electric Laboratories, Inc., a corporation of Delaware Application February 15, 1943, Serial No. 475,904

(Cl. 179-1ii) 16 Claims.

The present invention relates in general to signalling systems and more particularly to impulse repeaters for use in automatic telephone systems.

The object of the present invention is the provision of an improved impulse repeater, or long line adapter, for use with long telephone lines.

A feature of the present invention is the provision of a more sensitive receiving circuit at the exchange to insure quick and accurate response to dial impulses created at the subscribers instrument on long or heavily loaded telephone party-lines.

A further feature is a new and improved circuit network in which the impulse relay is a polarized relay having a plurality of windings included in both the line circuit and in local circuits to enable the impulse relay to quickly and accurately respond to the opening and closing of the line during impulsing, One of the windings of the impulse relay being connected in series with a condenser and is connected over the line and over a local circuit in such a manner that current flow in this winding is quickly reversed during impulsing to cause the relay to quickly respond to the subscribers dial impulses. In addition, this winding is connected in another local circuit of high resistance during each closed pulse period, after the condenser in the first mentioned local circuit is charged, and is thereafter eiiective so that this winding is preenergized in a direction to cause quick restoration of the impulse relay when the line is opened. The other winding of the impulse relay is also connected in series with the line and is connected in a local circuit in such a manner that current flow in this winding is likewise reversed during impulsing to assist in the operation of the relay so as to accurately follow the impulses. In addition the local circuit for this latter winding assists in maintaining the impulse relay in its released position during the open pulse period so that any minor line disturbances will not effect the relay. This latter winding is energized over the line during the line closure periods to maintain the relay in its operof Fig. l which relates to the impulsing arrangement.

Fig. 3 shows a modification of the repeater when used on a grounded line.

Fig. 4 illustrates diagrammatically that portion of Fig. 3 which relates to the impulsing circuits.

Referring now more particularly to Fig. 1 of the drawings, there is illustrated in partially schematic form a long telephone party line heavily loaded with ringers, an impulse repeater, or long line adapter, individual to and terminating the line in the telephone exchange, and the individual line circuit by means of which incoming and outgoing calls are extended from and to the automatic switching apparatus in the automatic exchange.

The line, comprising conductors I and 2, is a long telephone party-line having a plurality of subscribers substations, such as A, B and 0, connected thereto, At each substation there is a ringer and a condenser connected in series to one of the line conductors and ground. The line conductors l and 2 terminate in the automatic exchange in an individual impulse repeater, or long line adapter, comprising a plurality of relays and a repeating coil. The other end of the repeater terminates in the well-known line circuit, comprising the usual line and cut-off relays, used in automatic telephone, This line circuit is provided with the usual incoming and outgoing branches for completing calls to and from the line. The relays in the repeater are of the type used in automatic telephone systems except that "l relay is is a sensitive polarized relay having a permanent magnet and two windings, one a primary winding P and the other a second winding S. Polarized relays of this type are well-known and have been used in telegraph systems,

Fig. 2 diagrammatically shows only that portion of Fig. 1 which relates to the transmission of subscribers impulses over the line to the impulse receiving network at the exchange which is effective during impulsing to operate the polarized pulsing relay H3.

Corresponding apparatus in Figs. 1 and 2 have been given the same reference character or numeral. This form of circuit diagram in Fig. 2 has been shown in order to more readily see and understand the operation,

Fig. 3 illustrates the same repeater, as shown in Fig. 1, when connected to a grounded subscribers party-line In this figure the circuits are slightly altered so that this repeater will function properly over a grounded telephone party-line, such line comprising only a single conductor grounded at the substations on this line and also grounded at the exchange as illustrated. The alterations are easily noted when Fig. 3 is compared with Fig. 1 especially since corresponding apparatus have somewhat similar reference characters, in that such reference characters have been primed and the reference numerals increased by one hundred.

Fig. 4 diagrammatically shows only that portion of Fig. 3 which relates to the transmission and receipt of subscribers impulses over the grounded party lines, Corresponding apparatus in Figs. 3 and 4 have been given the same reference character or numeral.

The operation of the system will now'be de- '7 scribed in detail in connection with Figs. 1 and 2. For this purpose it will be assumed that subscriber A initiates a call by removing his receiver whereupon a circuit may be traced from ground thru the winding of relay 4!], winding'25 of repeat coil RP, back contact and armature 22, back contact and armature I2 out over the subscribers line conductor 2, calling device CD of substation A, switchhook contacts, line conductor I back to the exchange; armature II and back contact, armature 23 and back contact, winding 24 of repeat coil RP, tojunction point 29- where the circuit divides one'lbranch extending thru the winding of-relay 50 to battery and the other branch extending from junction point 29 by way of armature 33, prim ary winding P of the polarized pulsing relay Ill, and thru the condenser C to battery. Relays 4 B and 50 are energized in series over the calling subscribers loop and at armatures 50 and 5| complete an obvious circuit for energizing slow-to-release relay 90. The condenser C is charged over the previously traced circuit including the primary winding P, the subscribers loop and the winding of relay 40. The charging current thru the primary winding P is in a direction to cause the relay I to operate and close its armature II to thereby complete an operating circuit to the pulse repeating relay 80;

relay (not shown) in the line circuit; and at armatures BI and 92 connects battery and ground thru resistances R2 and RI respectively to the secondary win ding S of the polar impulsing relay I0.

, The pulse repeating relay 80,:upon energizing,

at armature BI completes another circuit for slow-to-release relay 90 in order to maintain this relay in operated position during dialling independent of armatures' II and at armature 82 connects ground by way of armatures 92 and 82 thru the high resistance R3 to the primary winding P and condenser C; and at armature 83 completes the loop circuit over conductors 3 and 4 for operating the line relay of the line circuit.

The line relay (not shown) in the line circuit operates and in the w ell-known manner and causes a line'switch or finder to operate and connect the conductors '3, and 4 to one of the first numerical switchesin the automatic exchange. Such numerical switch being either a selectoror connector dependent upon the number of subscribers lines being served by this exchange; Dial tone is transmitted back from the first numerical switch over conductors 3 and I and thru the repeat coil RP and over the subscribers line conductors I and 2 to inform the calling subscriber that he may now proceed to dial the digits of the desired called subscribers number.

Before proceeding with the dialling operation, we Will return to the time when relays and 99 operated to close certain local auxiliary circuits to aid in the operation of the impulsing polar relay Ill. When relays 80 and have operated, the circuits in Fig. 2 have been interconnected as shown- It will be remembered that condenser C is receiving a charge thru the primary winding P of relay I0 from over the line and thru the winding of relay 40. The current flow in this circuit is sufflcient to operate the polar relay in and before the condenser C is fully charged a holding circuit thru the secondary winding S is completed in such a dire"- tion to assist in the operation of the polar relay IO and to maintain the polar relay in its operated position after the condenser C is fully charged. The circuit thru the secondary winding S may be traced as follows: from ground thru the resistance RI to point 84 where the current divides one path extending over resistance R2 to battery and the other path extending thru the secondary winding S of relay '50, over the closed subscribers loop, and thru the winding of relay 50 to battery. The current flow in this latter path thru the secondary is in a direction to assist'in the operation of the polar relay 1i] and, also, is suificient to hold the relay in operated position after the condenser C is charged and no current flows in the primary winding P. Another local' circuit connects ground thru the high resistance R3 to the primary winding P of relay ID at junction point 86, this circuit is effective after the condenser C is charged to cause a slight current flow thru the primary winding P in the reverse direction. This circuit may be traced as follows: from ground thru the high resistance R3 to junction point 86 thru the primary winding P of relay I0, and thru. the winding of relay 5%! to battery. As will be noted this current is in the reverse direction to that of the condenser charging circuit but due to the high resistance of resistance R3 the current flow merely preenergizes the primary winding in a direction to cause the quick release of this relay when the line circuit is opened. The previously traced circuit thru the secondary winding S of relay I0 predominates over this preenergizing circuit of the primary winding to hold the relay operated until such time as the line circuit is opened. The polar relay I0 is therefore held in operated position until the subscriber starts to dial the calledsubscribers number or until the calling subscriber hangs up his receiver.

The resistance values of the resistances RI, R2 and R3 and the capacitance value of the condenser C, included in the local network circuits, have been carefully chosen and by actual practice have permitted very satisfactory performance over long telephone lines heavily loaded with ringers. The resistance value of resistance R2 in combination with resistance RI has been chosen to exceed the overall resistance of the line in combination with the battery feed relays 40 and 50 when the line is closed and should be less when the line is open in order to reverse the current in the secondary winding S. The capacity of condenser C mane-resisrof such: a .valuc as to -give '-:a..-sustained.charge:or ..discharge-::current flow thru. the primaryaw-inding .P *for a; predetermined time. .Therresistance value of theresistance ;R3 is relatively high-compared with the .lineresistance in combination with :the r:

previously traced ipreenergizing circuit for -this winding. eAt-theinstantthe line is opened the :ri-ngercondensers: in the lineare being charged but the discharge current fromcondensereC thru theprimary winding P hasa tendency to neutralize the charging current to-the ringer. condensers.

Also at the instant of line openingthere is. only momentarily a current flow thru the secondary winding Sina direction tomaintain. the-relay in .itsoperated position but due tothe-rapidrisein resistance in the line as the ringercondensers .are being charged, the. current fiowin the second- 'ary .winding Sisyery quickly reversed to assist the .primary winding in releasing relay in :toits released position. The local circuit, ior-thesecondary winding. S, duringthe -.open..pulse \period when the lineisiopen, may be tracedlasfollowsz from ground thru the winding oirelay mjunction point .28, armature 32,.secondary winding S,.j.unctionpoint .84, armature Bland thru resistanceRZ .to battery. The .currentfiow .in.this circuitis suflicientand in .a direction tcboth assistthe .primary winding 1P torelease the.relay .and maintainv said ,relay'in its released .position. This local ,circuit .for the secondary windings is effective before the condenser .C .is discharged. Pulserepeating relay 80 deene'rgizes 'in..r.esp onse to .the release .of rela 1-0 to disconnect. ground thru ;the high resistance .;R3 from .the,primary winding'P to open the previously traced preenervgizing circuit vfor the primary winding. When the condenser C is fully .dischargedin its"localcircuit no current'flows thrutheprimary winjding'and the relay In is maintained in its released position by the current flow in the secondary windingS'thruthe resistanceRZ. It should also bementionedrthat afterthedischarge .of condenser :C and when the line is open that relay .50 may "momentarily .release during 'diallingibut 1such releasing operatins of relay 50 areinefiective because the .relay 9U is slowacting:andwillbe maintained in operated position during "dialling.

The pulse repeating relay 801s operated :over an obvious-circuitby the-polar relay 10 erating its armature "TI and it should "bementionedthat the resistance R4 :and condenser Cl connect-s ground to junction pointll-to1.quench*the:sparks at armature "H and toact-asiaso-called ffpulsestretcher, in that, 'dueto-thecharging and-discharging circuit of'condensenCl, the pu-lse'repeating relay -80 somewhat lengthens i the pulses repeated at armaturefis =t'o'move inearly conforrn "to the standard pulsing rate normally used 'in automatic telephone systems. At armature =83, the pulse repeating relay repeats the pulsesaover the conductors 3 and 4 to the automaticswitches in the exchange to cause theseswitches-totem- TIO xplete :the desired :connection in .a well-known manner.

When the. calling .deviceiCD closestthedinercirtcuitzafter'the "open pulse period, "circuits are completed overithe line'for relays 40-and'50an'd for both the primary and. secondaryxwindingsof relay "!0. The circuit forrrelays 40. and r extends fromrground relay 40, over the'closedsubscribers .loop including "the windings 25 and 26 of *thc repeat "coil RP and the: line conductorsl and 2,

and winding of relay 50to"battery. The circuit for thesecondary windings extends'from: ground .at armature 92 thruresistance RI, secondary winding. S of relay 10, over the subscribersiline' 3 loop including the "repeat: coil windings. 24 and: 25, and thrutthe winding of relay 50 to battery. v1A 'rbranchof this latter circuit extendsfrom, junction :pointf29 and armature 33 thru the primary Winding P'of relay l0 andithruithetcondenser ()xto batteryfor chargingcondensenC thru the primary winding P. The current :flowin-the "secondary windings since the line is closed-and the;charging current flowing in the primary winding are in a direction toiaideachothertocauserelay 1'0 "to operate to its operated position. Since theresistance of resistance R2 is greaterithan the line resistance, comprising the subscribers-loopgthe current thru the secondary winding s again areverses to aid in the operation of relay 1-0 :as well as for maintaining the relay'in its operated-position'after condenser Clis charged.

Relay Hi, uponoperating, closes armature ill to again operatepulrerepeating relay which at armature 83 again-closes the loop to theauto- .matic switch train.

At armature 8| relaytl! againcloses-the circuit to slow relay and :at armature '82 "again connects ground :thru "high resistance R3 to .the primary winding Pthere- .by preparing the, previously described *preenergizing circuit :forthe primary v windingP *which is effective after the condenser C is charged. The previously traced circuit thru the secondary winding S maintains relay H1 in-operated position, as previously described, until the 'line is-opened for thesecond pulse of the called num- "-ber.

Further impulses of'the calledsubscribersnurnber cause the circuits and relays H1 and 8D to ffunction in the same manner .as'-.previously.de

scribedthereby-operating the automatic switches in the automatic exchange in the well-known -manner to complete the .desired connection.

Talking batter is fed thru'the windings ofbattery feed relays fl and 59; After conversation and in response to replacingthe receiver the subscribers'line is opened and relays "I0 and80 release to cause the release 'of "the automatic switch train. Relays 40 and 50 likewise release to cause the release of slow acting relay *9!) after a shortiinterval and'the repeater is now innor- :mal unoperated position.

Having described the operation of the repeater in connection With-an outgoing call from the I subscribers line, an incoming "call will now he described to one of the subscribers onthisline.

As will be noted, the ringers Li'to L3 at the various substations on this line are connected to oneof theline conductors and ground. Inorder to selectively ring a subscriber on this line divided code ringing is applied from an automatic connector switch. Automatic St-rowger connector switches of this type are well known and need not be described. '5 Patent 2,099,429 shows a Strowger connector switchutilizing di- -vided code ringing while Patent 2,023,239 shows an all-relay connector. switch utilizing the 1 same type of selective ringing arrangement. For-selectively signalling subscribers .A'and C ringing current is sent out'over the line 'conducto'r'l and the ringing code sentdetermines which subscriber A- or C'is'wan'te'd; "In a similar manner ringing'current is' sent out over line conductor 2"ior all subscribers having theirringers connected in the same manner as ringer L2 for substation B. It will now be' assumed that an-automatic switch'has been operated to co'nnect'with conductors'5, Band 1 individual to thisparty line and that the call is intended for subscriber A.

to line conductor I thereby operating all the ringers connected to line conductor I. At armature I2 relay I grounds the other line conductor 2 and at armature I3'complet es a circuit for operating slow' relay 30. Slow relay 30 also follows the ringing code and releases a short interval after ringing relay I0. Relay 30 at armatures 32 and 33 disconnects the windings of the sensitive polar'pul's'ing relay 10 from the line so that thisrelay will not be falsely operated during ringing. At armatures 32 and 34 connects ground and battery thru resistances R5 and R5 respectively to the windings of relays 50 and 50 to prevent false operation of these relays. Subscriber A, upon recognizing his ring and removing the receiver, completes the previously traced circuit for relays 40, 50 and when the relay 30 deenergizes after the'last ringing period. The operation of relays 80 and 00 take place in the same manner as previously described to close a bridge across conductors 3 and 4 to cause the connector to cut off any further ringing operations. The bridge circuit includes armatures 83 and 93, resistance R, repeat coil windings 26 and 21, conductors 3 and 4, conductors 1 and 5, and v the ring-cut-off relay in the connector switch. Talking battery is fed over the windings of relays 40 and 50 to subscriber A. After the conversation and in response to, hanging up the receiver at substation A relays 40, 50,10, 80 and 90 deenergize to restore the repeater to normal while the connector switch is released in the usual manner;

In case subscriber. B is being called then the connector switch applies ringing current to conto that described for relay I0 operates, slow relay 30 at armature 2|, at armature '23 grounds line conductor I by way of back contact and armature II, and at armature 22 connects generator GEN by way of conductor 2 to ring all of the ringers connected to conductor 2. Sub- "scriber- B up'on rr'e'cognizing his 'code ring-, answers by removin'g the receiver the'reby causingthe operation of 're1ays"4 0,"50, 10', and'90in the substation A and need not be described in detail.

Aspreviously' stated themodification shown in Fig. 3 is substantially the same repea/ter as shown in Fig.1'adapte'd for use on a grounded party line. Thisparty'line comprisesa single line conductor I0l' extending from the exchange and is grounded at the various substations onthe line. In this modification the pulsing'circuit-for the polarized relay "I10 isslightly difierent, in that the secondary winding S is now connected'in a reverse direction to that shownin Fig.1 and the resistances R2 and RI, corresponding respectively to resistances R2 and RI, are interconnected between battery and ground and the secondary winding in a slightly different manner.

The remaining circuits remain substantially the same except'that line conductor I02 is grounded at the exchange. Relays I20, I40 and I95 are not used in this circuit and have been shown merely to show the ease by which this repeater may be used for both loop and grounded party lines.

, When a subscriber on the line removes his receiver, relays I50, I10, I80 and I operate in a manner similar to that described for Fig. 1. v The circuit for relay I50 may be traced as follows: from ground at the callin substation, conductor l0I, back contact and armature I I I, armature I23and back contact, windings I24 and I25 of repeat coil RP; junction points II 5 and I29 where .the circuit divides, one path extending thru the winding .of relay I50 to battery. A branch of this. circuit extends from junction point I20, armature I33, thru the primary winding P. of the'polar impulsing rela I10, and thru the condenser C to battery to charge the condenser C. The charging .current flowing thru the primary winding P is sufiicient and is in a direction to operate relay I10 to its operated position to close its contacts I'II thereby oper .ating pulse repeating relay I80. Slow releasing tion of the flow of charging currentto condenser C. The circuit thru the secondary winding S may be traced as followszfrom ground at the calling substation over the. line conductor IOI and-the previously traced to junction point H5 and from thence by Way ofcontacts I 32, secondary 'winding s of relay. no, contacts HI, and thru resistance RI to battery. At contacts I92 relay I90 connects ground thru resistance R2 to the secondary winding S but since the value of the resistance of R2 is greater than the resistance of the ,line when closed this connection does not change the direction of current flow thru the secondary winding. At contact I82 relay I80 connects ground to winding P thru the high resistance R3 and this circuit is effective after the condenser C is charged to complete a preenergizing circuit thru the primary winding P in the reverse direction. This preenergizing circuit may be traced from ground contacts I92 and I82, high resistance R3, primary winding 1? of polar relay secondary winding 6, and resistance RI to batv I10, contacts I33, junction point I29, and thru the winding of relay I50 to battery. The flow of current in this preenergizing circuit is in a direction to cause the release of relay I10 but due to the high resistance of resistance R3 this flow of current is small and is inefiective at this time to release relay I10 due to the flow of current through the second winding S previously described which predominates thereover. The polar pulsing relay I10 therefore remains in operated position until the line is opened. Fig. 4 now illustrates diagrammatically all the circuits in the impulsing network which are now completed.

At contacts I83 and I93 relays I80 and I9 close a bridge, including resistance R and windings I26 and I21, across conductors I03 and I04 to cause the operation of the relays in the line circuit in the same manner as described for Fig. 1. Since the operation of the automatic switching apparatus is well-known and is the same as that described in connection with Fig. 1, no further explanation of such operations will be described.

The calling subscriber will now dial the number of the desired called subscriber. When the calling device CD is operated to open the line circuit, the local circuit for discharging condenser C is efiective to cause the release of polar pulsing relay I10. This local circuit may be traced from battery, condenser C, primary winding P of relay I10, contacts I33, junction point I29 and thru the winding of relay I50 back to battery. The flow of current thru the primary winding P in this local discharge circuit is sufficient and is in the proper direction to cause the polar pulsing relay to be operated to its released position thereby opening contacts I! I to release pulse repeating relay I80. Also when the line is opened the current flow thru the secondary winding S is reversed to assist in releasing relay I10 and to maintain such relay in released position as long as the line is open. Since the line is open the current flow thru the secondary may be traced over the following path: from ground at contacts 1-92, resistance R2 to junction point I84 where the current divides. -one-path-extend-' ing thru resistance R-I to battery and the other path extending from the junction point 184, thru the secondary winding *8,- contacts I32,-junct-ion points I I5 and I29, and thru-thewinding of relay I50 to battery. The current flow in this latter path thru the secondary winding S, is sufiicient and is the proper direction toassist the primary winding P to release relay I10 andfor maintaining relay I10 in released position afterithe discharge'current disappears; At contacts I-82 relay I80 disconnects ground thru high resistance R3 to open the local preenergizin circuit thru the primary winding P. Secondary winding S maintains the polar relay I10 in its released position until the line is again closed.

'Whenthe calling device CD closes the line after the'first pulse, -the previously traced circuits for relay 150 and the charging circuit for condenser C thru the primary winding P of relay I10 are again closed. Also, since the resistance value of R2 islgre'ater than the resistance value of'the line when closed current now flows thru the secondary winding S 'in a directionto aid the charging current thru the primary winding P of relay I10 to cause relay I10 to quickly operate to its operated position. This circuit .may' be traced from ground at the substation .over line conductor I'0I to junction point 'I I5; contacts I32,

tery. The flow' of current in this circuit also maintains relay I10 in opera-ted position after condenser C is charged and after the preenergizing local circuit; includingrlasistanceRB, is closed in the same manner as previously described.

Further dial impulses cause similar operations of relays I10 and I80 and the latter relay at contacts I83 repeats the impulses to the automatic switch train to complete the desired connection in th well-known manner.

After conversation and in response to replacing the receiver relays I50, I10 and I80 release and after an interval slow release relay I90 likewise releases to open the local circuit thru the secondary winding S. The apparatus is now at normal and may be used on subsequent calls.

Incoming calls to this line are similar to that described for Fig. l-except that ringing current is applied only to line conductor I03 to operate ringing control relay I60. Relay I60 at I6I operates ringing-relay -I I0 to repeat the ringing code out over conductor II. The called party, upon recognizing his code ring, removes the receiver thereby completing the circuits for relays I50, I10, I86 and I90 during a silent ringing period at which time relay I30is in deenergized position. At contacts Hi3 and I 93 relays I80 and I90 close'a bridge across conductors -I03 and I04 to out on the ringing current being transmitted from the connector switch.

While the invention has been'de'scribed in connection with .a long telephone party line heavily loaded with ringers, it willbe obvious that this impulsing arrangement is also adaptable for use in systems other than telephone systems where there is need 'for impulsing over long lines having similar characteristics.

What is claimed is:

1. In .a signalling systemya line, an impulsin relay having a first and a second winding, a circuit including said first'winding and said line in series completed in response to the closure of said line for momentarily energizing said first winding by current flow in one direction to operate said relay to its operated position, a circuit including said second winding and said line in series completed in response to the closure of said line for energizing said second winding by current flow in said one direction to assist in the operation of said relay and for maintaining .said relay in operated position, a local circuit for said first winding inefiective when the line is closed and effective in response to opening said line for momentarily reversing the direction of flow of current thru said first winding to operate said relay to its released position, and another local circuit including a resistance in series with said second winding ineffective when the line is closed and effective in response to opening said line for reversing the direction of current flow thru said second winding to assistin operation of said relay to its released position and for maintaining said relay in its released position.

2. In .a signalling system, a line, aniimpulsing relay having aiprimary winding anda secondary winding, a circuit including saidprimarywinding and said line in series completed ;.in responsewto the closure o'fsaidline for energizingsaid-winding to operate said. relay, a circuit including said secondary winding .andsaid line in series com-' pleted in response to the closure oi saidrline lfOI energizing said-winding to .assist in ;the;-operation of said relay and for maintaining said relay in operated position, and means for reversing the fiow of current thru both said primary and secondary windings in response to the opening of said line for energizing said windings in the reverse direction to releas said relay.

3. In asignalling system, a line, an impulsing relay having a primary winding and a secondary winding, a circuit including said primary winding and said line in series completed in response to the closure of aid line for energizing said winding to operate said relay, a circuit including said secondary winding and said line in series completed in response to the closure of. said line for energizing said winding to assist in the operation of said relay and for maintaining said relay in operated position, and local circuits for both said primary and secondary windings ineffective during the time said line is closed and efiective in response to the opening of said line to reverse current flow thru both said primary and secondary windings intheir respective local circuits for energizing said windings in the reversedirections to release said relay.

4. In a signalling system, a line, an impulsing relay having a first and a second winding, a condenser, a first line relay, a second line relay, means for closing said line, a circuit for operating'said first and second line relays in series with said line completed in response to the closure of said line; arcircuit including said first line relay, said line, said first winding of said impulsing relay, and said condenser in series for charging said condenser and for operating said impulsing relay to its operated position completed in response to the closure of said line, a slow relay operated in response to the operation of said line relays; a circuit including the second winding of said impulsing relay, said lin and said second line relay in series for assisting in the operation of said impulsing relay completed in response to the operation of said slow relay,.a resistance having a resistancevalue greater than the-resistance value ofthe line when closed and series with said first winding and said line circuit in series with said second winding for operating said relay to itsoperated position in response toeach line closure by current fiow over said line circuits in the same direction thru said first and second windings and comprising said local circuit for said first winding and said local circuit for said second winding for operating said relay to its released position in response to each line opening by current flow over said local circuits thru both said windings in a direction opposite to that of the current fiow in said line circuits. 7

6. In a signalling system, a line, an impulsing relay having a first and a second winding, a line circuit for saidfirst winding including said line and said first winding in series, a local circuit for said first winding excluding said line, a line circuit for said second winding including said lineand said second winding in series, a local circuit for said second winding excluding said line, means for transmitting impulses over said line by alternately opening and closing said line, and means comprising both said line circuit and said local circuit for said first winding and comprising both said line circuit andsaid local circuit for said second winding for reversing current fiow thru said first and second windings in response to eachopening and closing of said having a resistance value less than the resistance value of th line when open; a local circuit including said-firstline relay, said second winding of said impulsing relay, and said resistance in series completedin response to the operation of said slow relay, said local circuit being ineffective when the line is closed, a local discharge circuit for-said condenserincluding said first winding of said impulsing relay and said second line relay in series,' said local discharge circuit being inefiective when" the line is closed, means for transmitting impulses over said line by opening and closing said line whereby said first local circuit and said local discharge circuit are both rendered efiective in response to eachopening said line for reversing the direction of current fiow in said first and second windings of said impulsing relay to cause the operation of said relay to its released position, and a pulse repeating relay controlled by said impulsing relay for reline, and means comprising said line circuit line to alternately release and operate said relay in accordance with the operation of said transmitting means. i I v 7. In combination, a line, a relay having a first and a second winding, a condenser in series with said first winding; a charging circuit for said condenser including said line, said first winding and said condenser in series for operating said relay to attract its armature to its attracted position in response to closing said line, a discharging circuit for said condenser including said first winding and said'condenser in series and excluding said line for operating said relay to release its armature to its released position in response to opening said line, a circuit for said second winding including said line and said second winding in series for assisting said charging circuit to operate said relay to its attracted position in response to closing said line and for maintaining said relay in its attracted position after said condenser is charged, and anothercircuit for said secondary winding excluding said line for assisting said discharging circuit to operate said relay,to its released position in response to opening said line and for maintaining said relay inits released position after said condenser is discharged. i

8. In combination, a line circuit, an impulsing 'winding including said first winding and said condenser in series and excluding said line circuit, and a sender at the remote end of said line.

circuit'for closing and opening said line circuit to control the operation of said relay over said impulsing circuits in response to closing said line circuit and to control the release of said relay over said local circuits in response to opening said line circuit;

In combination, a. l circui n impu se relay having a first and second winding, a condenser, a charging circuit for said condenser including said first winding and said line circuit in series, a local discharging circuit for said condenser including said first winding and said condenser in series and excluding said line circuit, a circuit for said second winding including said second winding and said line circuit in series, a resistance, and a local circuit for said second winding including said second winding and said resistance in series and excluding said line circuit.

10. In a signalling system, a line, an impulsing relay having a primary winding and a secondary Winding, a condenser; a circuit for charging said condenser including said line, said primary winding and said condenser in series completed in response to the closure of said line for operating said relay, a circuit including said secondary winding and said line in series completed in response to the closure of said line for assisting in the operation of said relay and for maintaining said relay in operated position after said condenser is charged and while said line is closed, a resistance having a resistance value greater than the resistance value of said line when closed, said resistance connected in a local circuit in series with said secondary winding and connected in shunt of said line, and means for discharging said condenser thru said primary winding and for establishing current flowover said local circuit including said secondary winding and resistance in series in response to opening said line to thereby reverse current flow thru both said primary and secondary windings to release said relay.

11. In a signalling circuit, a line, an impulsing relay having a primary and a secondary winding, a condenser; a circuit for charging said condenser including said line, said primary winding and said condenser in series completed in response to the closure of said line; the condenser charging current in said circuit thru said primary winding being suflicient and in a direction to operate said relay, a circuit including said secondary winding and said line in series completed in response to the closure of said line for assisting in the operation of said relay and for maintaining said relay in operated position after said condener is charged, a local circuit for reversing the current flow in said secondary winding, 8. local circuit for discharging said condenser thru said primary winding, both said local circuits effective in response to opening said line to reverse the current fiow thru said primary and secondary windings to release said relay, and said local secondary circuit maintaining said relay in its released position after the discharging current in said local primary circuit is dissipated.

12. In a signalling system, a line, an impulsing relay having a primary and a secondary winding, a first circuit including said line and said secondary winding in series, a condenser; a second circuit including said line, said primary winding and said condenser in series; means for closing said line to establish current flow over said first circuit thru said secondary winding and to charge said condenser thru said primary winding by current fiow over said second circuit to operate said relay, a local discharge circuit for said condenser including said primary winding, means for causing said condenser to discharge thru the primary winding over said local circuit in response to opening said line thereby reversing the current thru said primary winding to release said relay, and another local circuit efiective in response to opening said line for reversing the current flow thru said secondary winding to assist in releasing said relay to its released position. 13. In a signalling system, a line, an impulsing relay having a primary and a secondary winding, a first circuit including said secondary winding and said line in series, a condenser; a second circuit including said line, said primary winding and said condenser in series; means for closing said line to establish current flow over said first circuit thru said secondary winding and to charge said condenser thru said primary winding by current flow in said second circuit to operate said relay, the current flow in said first circuit maintaining said relay operated after the condenser in said second circuit is fully charged, a local discharge circuit for said condenser including said primary winding, a local circuit for said secondary winding, means responsive to opening said line for rendering both said local circuits eifective to reverse the current flow thru said primary and secondary windings to release said relay, and said local secondary circuit being effective after the discharge current is dissipated in said local primary circuit to maintain said relay in its released position.

14. In a signalling system, a line, an impulsing relay having a primary and a secondary winding, a first circuit including said secondary winding and said line in series, a condenser; a second circuit including said line, said primary winding and said condenser in series; means for closing said line to establish current flow over asid first circuit thru said secondary winding and to charge said condenser thru said primary winding by current flow in said second circuit to operate said relay, means responsive to the operation of said relay for closing a preenergizing circuit for said primary winding, said preenergizing circuit effective after said condenser is charged to reverse the direction of current flow in said primary winding preparatory to releasing said relay, the current flow in said first circuit maintaining said relay operated after said condenser in said second circuit is fully charged, a local circuit for discharging said condenser thru said primary winding with current flow in the same direction as in said preenergizing circuit efifective in response to opening said line to release said relay, a local circuit for reversing the current flow in said secondary winding efiective in response to opening said line to assist in releasing said relay and for maintaining said relay released after the discharge current in said first mentioned local circuit is dissipated, and said last mentioned means opening said preenergizing circuit in response to the release of said relay.

15. In a signalling circuit, a line, an impulsing relay having a primary winding and a secondary winding, a condenser; a circuit for charging said condenser including said line, said primary winding and said condenser in series completed in response to the closure of said line; the condenser charging current thru said primary winding being sufficient and in a direction to operate said relay, a circuit including said secondary winding and said line in series completed in response to the closure of said line for assisting in the operation of said relay, a local circuit for reversing the current flow in said secondary winding, a local circuit for discharging said condenser thru said primary winding, and both said local circuits effective in response to the opening of said line to reverse the current flow thru said primary and secondary windings to release said relay.

16. In a signalling system, a line, an impulsing relay having a primary and a secondary winding,

a condenser, a local discharge circuit for said condenser including said primary winding, means for closing said line and for completing a charging circuit for said condenser over a circuit including said line and said primary winding in series, means responsive to the closure of said line for completing a circuit for said secondary winding in series with said line and for completing a local circuit for said secondary wnding, said 10- cal discharge circuit and said local secondary winding circuit being ineffective when the line is closed, the condenser charging current in said charging circuit thru said primary winding being sufilcient and in a direction to operate said relay, the current flow over the circuit including said line and said secondary winding in series being in a direction to aid in the operation of said relay and being sufiicient to maintain said relay in operated position after said condenser is charged, said local discharge circuit and said local circuit for said secondary winding effective in response to opening said line to reverse the current flow in said primary and secondary windings to release said relay, the discharge current bein sufficient and in a direction to release said relay and the current flow in the local circuit for the secondary being in a direction to aid in the release of said relay and sufficient to maintain said relay in its released position.

- HARRY G. EVERS.

GEORGE ELLIOTT. 

